Shuttle guiding and driving means in wave weaving looms



H. mmm ,2339633 SHUTTLE GUIDING AND DRIVING MEANS IN WAVE WEAVING LOOMS 4 Sheets-Sheet 1 mh um@ M. mm www@ SHUTTLE GUIDING AND DRIVING MEANS IN WAVE WEAVING LOOMS Filed July l5, 1963 4 Sheets-Sheet 2 Feb. 8, 1966 H. FEND 3,233,533

SHUTTLE GUIDING AND DRIVING MEANS IN WAVE WEAVING LOOMS Filed July 15. 1963 4 Sheets-Sheet 5 .l Y y, l

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H. FEND Feb. 8, 1966 SHUTTLE GUIDING AND DRIVING MEANS IN WAVE 'WEAVING LOOMS 4 Sheets-Sheet 4 Filed July 15, 1963 United States Patent O 3,233,633 SHUTTLE GUiDiNfG AND DRU/ENG MEANS EN WAVE WEAVNG LMS Heinrich Fand, Regensdonf, Zurich, Switzerland, assigner to Verwaitungsgeseilschatt der Werkzeugmaschinenfabrik (Berliiron, Zurich, Switzeriand Filed July i5, 1963, Ser. No. 2%380 Claims priority, application Switzerland, .luiy 23, 1962, 8,796/62 6 Claims. (Cl. i39--12) The present invention relates to weaving machines, especially to so called wave weaving machines, and more particularly to the weft thread inserting means of these weaving machines.

Such weaving machines may comprise shedding means by which selected warp threads are deflected in such a manner that they are formed into sheds of limited width, a plurality of such sheds being caused to progress at a distance behind each other across the warp in the manner of travelling waves. In each of these sheds, a weft carrying shuttle is moved across the warp and behind the shuttle, the weft yarn delivered by it is batted down against the fell of the fabric by a group of reeds before the shed is changed at the place where the weft yarn has been delivered.

The main object of the present invention is to provide means for guiding and driving the several shuttles across the warp.

It has already been suggested in a weaving machine of this kind to provide groups of blade shaped shuttle guiding members arranged side by side and adapted to move group-wise into and out of the shed space between the warp threads in planes parallel to each other and to the planes of deflection of the warp threads, so as to form guideways for the shuttles within the respective sheds, but to retract from the shed behind each shuttle to permit the weft yarn delivered by the shuttle to be batted down by a group of reeds still within the shed. According to this suggestion, the shuttles should have been driven by electromagnets mounted on the shuttle guiding members outside the warp shed space. These members act as pole pieces for leading the magnetic flux into and out of the shed and along the track which they form for the shuttle, and it is therefore unavoidable that the electromagnets are moved together with the guide members. Since the electromagnets are comparatively heavy, it is not possible with that arrangement to move the guide members into and out of the sheds at the high speed required for fast operation of the weaving machine.

In another arrangement embodied n a circular loom, it has been suggested to rely, for the driving of the shuttles, on the shed changing motion for driving the shuttles. According to that arrangement each shuttle is provided with a lateral guiding blade extending lengthwise of the shuttle. The shed changing motion is efected by eyed slides each of which not only serves for individually deflecting a warp thread running through its eye, but each of which also has a pair of notches facing each other and forming a gate for the passage of the said guiding blade of each shuttle. The edges of the guiding blade each comprise a guiding surface paraln lel to the direction of movement of the shuttle and, at the rear thereof, an inclined driving surface converging at an acute angle with the corresponding driving surface at the opposite edge. Whenever two of the said slides move in opposite directions in their shed changing motion, while one of the said notches of one of them is engaged on one of the driving surfaces of a shuttle and the opposite notch of the other is en-gaged on the opposite driving surface of that shuttle, the latter becomes moved across the Warp by the relative displacement of the two slides.

However, this arrangement as well has a number of drawbacks. The guiding blade must be rather long to ensure proper guidance of the shuttle, and thus a substantial number of the said slides are involved in the guiding of the shuttle in each shed. This reduces the number of sheds which can be formed and the number of shuttles which can be used simultaneously in a given weaving width, which, with a given shuttle speed, results in a low rate of production. Moreover, such shuttles have too short driving surfaces, so that only few of the shittable plates can engage each of them at a time, and strong wear occurs. A further disadvantage of this device consists in that it does not permit backing the shuttles out of the warp by mere reverse operation, e.g. in view of repairing faults in the weave.

it is therefore an object of the present invention to provide improved guidance for even short shuttles by the driving members, which will permit these to be moved in accordance with a waveform of comparatively short wavelength.

Another object of the invention is to provide an arrangement which permits an increased number of shuttles to travel simultaneously behind each other across the weave so as to ensure a hi-gh rate of production at a given shuttle speed.

Still another object of the invention is to permit the use of shuttles of small length, reduced weight and requiring smaller driving forces.

A further object oi the invention is to provide a shuttle driving arrangement which is suitable for reverse displacement of the shuttles in the unweaving of a faulty portion of the fabric.

An embodiment of the invention and various modifications will now be described solely by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a vertical section through the shuttle drive mechanism of a flat wave weaving machine, with packets of reed teeth fitted for batting-down the weft thread and with a shuttle in the shed, some components lying further back being omitted;

FIGURE 2 is a front elevation of the same arrangement with the casing broken away and the reed teeth partly broken off;

FGURE 3 is a plan view diagrammatically showing the displacement waveform of the shuttle driving members, with the reed teeth partly broken off, and showing one shuttle;

FIGURE 4 is a detail of FIGURE 1 on a larger scale;

FIGURES 5 and 6 are a plan View and side elevation, respectively, of a modified shape of the shuttle and associated driving members, on a larger scale; and

FEGURES 7 to 9 diagrammatically show further modifications of the shuttle in section on line VII-VH of FIGURE 4.

The weft thread inserting means which will be described hereinaiter are part of a multiple shuttle wave weaving machine or progressive shedding loom which otherwise may be of known construction. in this loom, the warp threads 25 delivered by a warp beam (not shown) are supported generally parallel to each other and to the plane of FIG. l, rearwardly of the shed-forming and weft inserting means by a iixed supporting bar F extending across the loom. In front of such means, the

woven fabric 62 containing the said warp threads passes over a supporting roller 63 which also extends across the loom, and thence proceeds to a take-oit beam (not shown).

ln front of the supporting bar, the warp threads 25 run each through the eyes 64 of one of a row of heddles d5'. These heddles are mounted each in one of a number, two in this instance, of shafts 66 which are dispose one behind the other. For example, alternate heddles d may be mounted in the rear shaft and the remaining alternate heddles may be mounted in the front shaft, but depen-din0r on the weave pattern, the heddies may be distributed differently on the several shafts and there may be more than two of these shafts arranged behind each other.

The shafts of each set, i.e. the shafts 66 situated behind each other, are moved up and down by means not shown in order to deflect the respective warp threads 25 upwards and downwards in planes parallel to each other and parallel to the plane of PEG. l, to form them into sheds adapted to contain travelling weft-inserting shuttles 16. While in conventional looms each shaft, and accordingly the shed controlled by one set of shafts, may extend over the whole width of the loom, in the multiple shuttle looms of the kind here contemplated at least twice as many sets of shafts 6d are juxtaposed over the width of the loom as there are shuttles le operating at the same time so as at any moment to provide one fully open shed for accommodating each shuttle, and to provide between the sets of shafts forming consecutive open sheds, at least one set of shafts which are free to move for changing their respective shed before the next shuttle enters it.

The space defined by the uppermost and lowermost positions of the warp threads 2S and within which all sheds are formed and changed will hereinafter be termed the warp shed space.

The shuttle drive mechanism shown in FGURE l comprises a pair of cam shafts 9 and 9o, rotatably supported parallel to each other in a casing 32. To these cam shafts, sets 3 and 4, respectively, of cam discs are fitted by means of keys l@ and 19a, respectively, which cam discs are individually denoted 3a, 3b, 3c, 3d ctc. and da, 4b, 4c, ftd etc. in FGURE l and are arranged one behind the other as viewed in FIGURE l. Each of these cam discs is angularly offset a certain amount relative to the subsequent cam disc on its respective cam shaft 9, 9d. On an axle 6, levers l with rollers 2 are mounted pivotally independently of each other; these levers are individually denoted lla, lb, 1c etc. and their respective rollers 2a, 2b, 2c etc. are journalled on pins 5a, 5b, 5c respectively. Each roller is arranged between a pair Zia-4a, Sb-lb etc. of cam discs, respectively.

A plurality 7 of slides, individually denoted 7n, 7b, 7c etc., and constructed as members for driving and completely guiding the shuttles lo, are guided in parallel slots 8 provided side by side in the housing 32 and extending generally in the direction of the warps. ln the top of the casing 32, there is a cut-out from below extending over the length B, through which the levers l reach upward into the slots 8, in which they are guided laterally. On the levers l, slider blocks lll are mounted, which have the same width as the levers l themselves and are guided each in the same slot as the associated lever. These levers l maintain said slider blocks lll engaged from below in recesses of the slides 7.

rl`he cam discs 3, d are so designed that, upon synchronous rotation of the two shafts 9 and 9a, they are permanently in a play-free Contact with the rollers Z. They all have the same configuration but are keyed to the respective shafts in equally spaced angular positions so that they move the slides '7 by means of the levers l to-and-fro between a rear end position and a forward batting position in an identical manner but with a phase offset, in accordance with a predetermined travelling waveform. A dovetail-shaped slot t3 extending transversely of the slots d over the full width of the casing 32 serves for accommodating a ledge l2, which in turn holds all the slides 7 in the slots 8.

As shown in FlGURES l and 4, the slides 7 carry at their left hand side ends a forked projection lili having a recess l5. This recess separates two upwardly directed legs, the forward one of which is shorter than the rearward one and has a flat top surface ll7 parallel to the direction in which the slide is displaceable. Arcuate shuttles ld each having a likewise arcuate rib 2@ on its under face have two Hanks 2l. and 3l (FIGURE 3) of that r'b engaged into a crescent-shaped guide formed by the rearward edges 19 and tne forward edges 1S, respectively, bounding the recesses l5 in the forked projections of a plurality of those slides 7 which under the control of the respective cam discs 3 and -tdcne, in the said travelling waveform, a wave trough facing the fell 2'5 of the fabric.

On its outer side (facing to the left in FiGURE 4), the outer flank 2l of the shuttle le is embraced over its whole length by the abutments or edges 19 which bound the recess i5 in the projections to the rear, and likewise the inside flank 3l of the guiding rib Ztl of the shuttle is aged by the abutmcnts or edges l bounding the said recesses forwardly. The two edges l8 and 19 converge upwardly, the recesses 3.5i widen downwardly. Since the rib 2t? has a prole corresponding to the recesses l5', the shuttle, which at its underside rests on the fiat top surfaces l/ of the projections ld, is firmly guided in these projections, so that it can move only laterally in accordance with the movement of the slides "i.

To engage properly the abutments or edges lle and 19 bounding the recesses l5 in the projections liti of the sevkeral slides '7, the flanks 2l and 3l of the shuttle rib 2d are conligurated each as a surface defined, on one hand, by a lead line situated in a reference plane coinciding with the plane indicated by line VII-VII in FG. 4, which plane is parallel to the direction in which the slides 7 are displaceable. Gn the other hand, each of these surfaces is defined by generating lines all similarly coniigurated, parallel to cach other and intersecting the said lead line. The lead lines of the surfaces forming the flanks 2l and 3l of the shuttle ri'o 2@ are configurated like a portion of the wave line defined by the points of intersection of the edges and l, respectively, with the aforementioned reference plane, said portion of the Wave line forming, in the example illustrated in FlGS. l to 4, a wave trough facing the fell 26 of the fabric. lt will be noted that lead lines defining the surfaces of the outer flank 2l and of the inner flank 3l, respectively, of the rib 20 are olfset from each other by invariable distance a (see FIGS. 3 and 4) in a direction parallel to the direction of displacement of the slides 7. rl`he generating lines of the surfaces forming the Hanks 2l and 3l, in the same example, are similarly configurated as the edges l@ and 23, respectively, that is, they are straight line portions of which those defining the outer flank 2l are substantially perpendicular to the plane of reference Vil-VH and those defining the inner lank 3l form an angle somewhat smaller than with the said. reference plane.

Accordingly, the rib 2t* of each shuttle 16 accurately tits the recesses l5 in the forked projections lli of a nurner of slides '7. ln the example of FIGS. l to 4, the edges t8 and 3.9 are straight and the flanks 21 Iand 3l therefore will be constituted by ruled surfaces. However, the edges l and lh* could be of arcuate form and the flanks and 3l of rib 2t? would then have a different coniicuratio-n defined by the same lead lines. lf the path of the slides 7 were :arcuate rather than straight, the lead :lines to be considered would lie in a reference surface other than a plane such as that exemplified by the plane Vil-VH in the present example and its modifications.

A convenient shape of the travelling wave is illustrated in FlGUlE 3. The shape shown repeats itself any time after an angular onset of 360 of the cam discs so that permanently five to eight of such waves are formed. The travelling waves thus formed bythe projections f4 proceed in one or the other direction transversely of the warp threads depending on the sense of rotation, and thus carry along the shuttle lo lyin.fr in the said wave trough facing the fel 2d of thc fabric. Each shuttle l@ is in engagement only with a predetermined number of slides 7, namely with those which actually form the trough of the wave.

In addition to the projection 14, a group 27 of reed teeth 22 is mounted on each slide, which group is held together by means of a connecting member 23. Each slide 7 together with its group 2'? of reed teeth is exchangeable; for this purpose, however, the ledge 12 and the cover 3S are to be removed. The warp threads 25 which form the weaving shed pass between the individual reed teeth 22 on their way to the fell Z6 of the fabric, thus enclosing a space in which the shuttle is held by the projections 14 of the slides 7. rhe individual reed teeth 22 of each group are moreover connected at their upper ends by outer connecting members 24. The reed teeth 22 serve for batting down the weft thread on the fell of the fabric in the forward batting position of the slides 7, in which the projections 14 have emerged from the weaving shed.

As will be seen in FIGURE 3, owing to the favounable shape of the shuttle 16 and to the comparative shortness of the travelling wave it is possible to keep the slides at a standstill in their forward batting positions for a short while, in order to attain in this manner a favounable binding in of the freshly inserted weft thread.

In a cavity (not shown) of the shuttle 16 the weft thread 2S is stored, which runs from there to the fell 26 of the fabric. In order to keep the shuttle small, prefer- Iably only a storage of weft thread corresponding to the width of the weave is accommodated therein.

In FIGURE 3, the slide 7a is in its rear dead center position and accordingly is at a standstill for a moment. All the slides located further down in FIGURE 3 are moving towards the left in the direction of the arrow, some of their forward edges 1S cooperating with a driving portion 51 of the flank surface 31 of the shuttle rib 20 which is inclined relative to the driving direction, and shift the shuttle 16 downwardly as seen in FIGURE 3. Similarly, all the slides, which in FIGURE 3 are shown above the slide 7a and which are not yet in their forward batting position, move in the opposite direction, i.e. to the right in FIGURE 3. The rear edges 19 of the recesses of some of them cooperate with a driving portion 52 of the fiank surface 21 and push the shuttle 16 in the same direction, as do the other slides, i.e. downwardly in FIG- URE 3. The straight line guidance of the shuttle on a track parallel to the fell 26 of the fabric is taken care of by the same slides, which are in motion, since the rear edges I9 of the recesses l5 of those slides which are shown below the slide 7a cooperate with a guiding portion 53 of flank surface 2l, and the forward edges 13 of the recesses of those slides which are shown above the slide 7a cooperate with a guiding portion Se of flank surface 31.

When it is necessary to back the shuttles out of the weave because of a fault in weaving, all directions of movement are reversed. The slide '7n is again at a temporary standstill while all the slides shown in FIGURE 3 below that slide move to the right, and all slides above it move to the left or stand still in their forward batting position. The former driving surface portions S1 and 52 now become guiding surface portions, and the former guiding surface portions 53 and 54 become driving surface portions by cooperating with the rear edges of the lower slides, and with the forward edges of the upper slides, respectively, and the shuttle is accordingly moved upward in FIGURE 3 in an analogous manner.

FIGURES 7, 8 and 9 illustrate three modifications of the shuttle 16 shown in its environment in FIG. 3. These modifications differ from the shuttle 16 in that according to them the rib 20, by which the shuttle engages the recesses 15 in the projections 14 of the several slides 7, is differently configurated in horizontal cross-section as taken in the reference plane indicated by the line VII- VII of FIG. 4. However, this rib in each case has the same cross-section, taken in any plane perpendicular to d the direction of displacement of the shuttles, as the rib 20 of the shuttle 16 as shown in FIGS. l and 4.

In the modification of FIG. 7, the outer flank 21 of the rib 2f) is defined by a line having an arcuate portion 38, a straight portion 41 and another arcuate portion 39, while its inner liank 31 is defined by a line parallel thereto comprising an arcuate portion 40, a straight portion 42 and another arcuate portion 37. Geometrically speaking, these lines 37 to 42 are portions of lead lines for the ruled surfaces which constitute the said flanks of the rib 2t). For the direction of movement indicated in FIGURE 7 by an arrow pointing towards the right, the lead line poition 38 of the driving surface starting with an inclination with reference to the direction of movement joins the middle lead line portion 41 of the guiding surface which runs parallel to the direction of movement, and the portion 41 joins the lead line portion 39 which ends with an inclination opposed to that of the portion 38. The lead line 4) of the guiding surface likewise starts at an inclination to the direction of movement and joins the lead line portion 42 of the guiding surface which is parallel to the direction of movement; the latter in turn joins the oblique lead line 3'7 of the driving surface. In a manner analogous to that described hereinabove, the surfaces defined by the lead lines 37, 38, 39, 4f) exchange their functions from that of driving to that of guiding, and vice versa, when unweaving. The lead line portions 39, 4t) of the guiding surfaces are parallel to the correspending lead line portions 37 and 38, respectively, of the driving surfaces and offset with reference to them by the width a of the recess 15 in the forked. projection 14 of each slide, as measured in the aforesaid sectional plane VII-VII (see FIGURE 4). The same odset is also to be found between corresponding lead line portions 41 and 42 of the guiding surfaces. However, these latter do not interchange their functions when the direction of movement of the shuttle is reversed.

The modification of a shuttle illustrated in FIGURE S has guiding surfaces in the form of ruled surfaces defined by lead line portions d4, 45, 46, which in their course likewise assume different directions relative to the direction of movement of the shuttle, namely from an initial inclination with respect to the direction of movement up to parallelism therewith. @ne portion 44 of the lead line of the guiding surface is offset the amount a parallel to the corresponding portion 43 of a lead line defining a driving surface, the lines 44 and 43 likewise exchanging their functions as regards driving and guiding depending on the direction of movement of the shuttle.

In FIGURE 9 a modification is illustrated of a shape similar to that shown in FIGURE 3. However, the shuttie accordinf7 to FIGURE 9 no longer has a continuous rib, but two partial ribs 20a and 25th, the shuttle being in contact with moving slides only. For the direction of movement indicated in FIGURE 9, i.e. to the right there are guiding surfaces defined by a lead line portion 50 inclined in one sense to the direction of movement, and a lead line portion 429 inclined in the other sense, which lead lines are offset the distance a from lead lines 47 and 48, respectively defining ruled driving surfaces. j

In the shuttle 35 illustrated in the FIGURES 5 and 6 the forks 36 embrace the shuttle as a whole instead of only a rib thereof. However, the forks in their cooperation provide likewise complete guidance of the shuttles while at the same time driving the same, owing to their particular construction with a bulge 51, which engages a corresponding groove in the one flank of the shuttle.

I claim:

1. In a weaving machine, weft thread inserting means comprising a plurality of similar shuttle driving members arranged side by side, means for displacing said driving members along similar paths all parallel to a common surface of reference, a pair of oppositely facing shuttle engaging abutments spaced from each other in the direction of displacement of the respective shuttle driving member on each of said shuttle driving members, actuating means for reciprocating said shuttle driving members individually along their said paths in phase oiset relation with respect to each other such that the intersections of one of said shuttle engaging abutments of said shuttle driving members With said surface of reference define a first lead line travelling along said surface of reference in a direction perpendicular to the direction of displacement of each of said shuttle driving members when reciprocated in said phase offset relation, whereby the intersections of the other of said shuttle engaging abutments of the same members define in said plane of `reference a second lead line olset by an invariable distance from said first lead line in the direction of displacement of said shuttle driving members and travelling jointly With said rst lead line in the same direction as the latter, and a plurality of Weit thread carriying shuttles each having a pair of oppositely facing cam surfaces the iirst of which is deined by a part of said rst lead line whereby it is engageable by said one shuttle engaging abutnients of several of said shuttle driving members at a time, and the second of said cani surfaces is similarly defined by the corresponding part of said second lead line whereby it is engageable by said other shuttle engaging abutments of the saine shuttle driving members, the said part ot said rst lead line and the said corresponding part of the second lead line comprising each at least tvvo portions differently inclined with reference to said travelling direction.

2. Weit thread inserting means as claimed in claim l in which said lead lines of the cam surfaces of each shuttle are similarly congurated for at least half of the abutment front line in which said abutments engage said cam surfaces.

3. Weit thread inserting means as claimed in claim 1 in which the mutually engageable surfaces of the shuttles and shuttle driving members are congurated for providing complete linear guidance and control of the shuttles.

4. Weit thread inserting rneans as claimed in claim 1 in which said abutments of each shuttle driving member are constitued each by one surface laterally bounding a recess in said portion of the shuttle driving member, said recessbounding surfaces diverging towards the bottom of said recess, and said earn surface on each shuttle diverging accordingly to one side of said lead lines defining them.

5. Weit thread inserting means as claimed in claim l in which each of said shuttles comprises a rib the flanks of `which are congurated to form said Cain surfaces.

6. Wett thread inserting means as claimed in claim 5 in which each of said shuttles has a supporting surface partly surrounded by said rib, and each of said shuttle driving members has a portion congurated to deline a supporting abutment located and coniigurated for engagement With said supporting surface of any shuttle the said cam surfaces ot" which are contacted by the rst pair of abutments of the driving member.

Rcierences Cited by tire Examiner UNITED STATES PATENTS 720581 2/i903 Salisbury 139--12 1,723,426 ri/i929 .iones 139-15 FGREIGN PATENTS 1,237,034 6/1960 France.

DONALD W. PARKER, Primary Examiner. 

1. IN A WEAVING MACHINE, WEFT THREAD INSERTING MEANS COMPRISING A PLURALITY OF SIMILAR SHUTTLE DRIVING MEMBERS ARRANGED SIDE BY SIDE, MEANS FOR DISPLACING SAID DRIVING MEMBERS ALONG SIMILAR PATHS ALL PARALLEL TO A COMMON SURFACE OF REFERENCE, A PAIR OF OPPOSITELY FACING SHUTTLE ENGAGING ABUTMENTS SPACED FROM EACH OTHER IN THE DIRECTION OF DISPLACEMENT OF THE RESPECTIVE SHUTTLE DRIVING MEMBER ON EACH OF SAID SHUTTLE DRIVING MEMBERS, ACTUATING MEANS FOR RECIPROCATING SAID SHUTTLE DRIVING MEMBERS INDIVIDUALLY ALONG THEIR SAID PATHS IN PHASE OFFSET RELATION WITH RESPECT TO EACH OTHER SUCH THAT THE INTERSECTIONS OF ONE OF SAID SHUTTLE ENGAGING ABUTMENTS OF SAID SHUTTLE DRIVING MEMBERS WITH SAID SURFACES OF REFERENCE DEFINE A FIRST LEAD LINE TRAVELLING ALONG SAID SURFACE OF REFERENCE IN A DIRECTION PERPENDICULAR TO THE DIRECTION OF DISPLACEMENT OF EACH OF SAID SHUTTLE DRIVING MEMBERS WHEN RECIPROCATED IN SAID PHASE OFFSET RELATION, WHEREBY THE INTERSECTIONS OF THE OTHER OF SAID SHUTTLE ENGAGING ABUTMENTS OF THE SAME MEMBERS DEFINE IN SAID PLANE OF REFERENCE A SECOND LEAD LINE OFFSET BY AN INVARIABLE DISTANCE FROM SAID FIRST LEAD LINE IN THE DIRECTION OF DISPLACEMENT OF SAID SHUTTLE DRIVING MEMBERS AND TRAVELLING JOINTLY WITH SAID FIRST LEAD LINE IN THE SAME DIRECTION AS THE LATTER, AND A PLURALITY OF WEFT THREAD CARRYING SHUTTLES EACH HAVING A PAIR OF OPPOSITELY FACING CAM SURFACES THE FIRST OF WHICH IS DEFINED BY A PART OF SAID FIRST LEAD LINE WHEREBY IT IS ENGAGEABLE BY SAID ONE SHUTTLE ENGAGING ABUTMENTS OF SEVERAL OF SAID SHUTTLE DRIVING MEMBERS AT A TIME, AND THE SECOND OF SAID CAM SURFACES IS SIMILARLY DEFINED BY THE CORRESPONDING PART OF SAID SECOND LEAD LINE WHEREBY IT IS ENGAGEABLE BY SAID OTHER SHUTTLE ENGAGING ABUTMENTS OF THE SAME SHUTTLE DRIVING MEMBERS, THE SAID PART OF SAID FIRST LEAD LINE AND THE SAID CORRESPONDING PART OF THE SECOND LEAD LINE COMPRISING EACH AT LEAST TWO PORTIONS DIFFERENTLY INCLINED WITH REFERENCE TO SAID TRAVELLING DIRECTION. 